Frame for fluid machines

ABSTRACT

Herein described is a frame ( 10 ) for a fluid machine of the reciprocating type. The frame ( 10 ) bears one or more cylinders ( 12 ) moving inside each of which, with a reciprocating movement, is a piston operated by a crankshaft ( 14 ). The frame ( 10 ) is made up of one or more modules ( 20 ) of the same size and shape, within each one of the modules ( 20 ) being provided a single chamber ( 16 ) adapted to accommodate the crank mechanisms of each single cylinder ( 12 ). Each module ( 20 ) is further provided with a pair of opposite side walls ( 22, 24 ) and with one or more fixing means ( 26 ) which allow rigid coupling to each other, adjacently arranging their respective side walls ( 22, 24 ), of two or more of the identical modules ( 20 ) for providing a frame ( 10 ) for fluid machines provided with two or more cylinders ( 12 ).

The present invention regards the fluid machines and, more in particular, it refers to a frame for reciprocating compressors.

As known, a compressor is a special kind of machine capable of exploiting the task performed by an engine to increase the pressure of a compressible fluid (gas or vapour). In reciprocating compressors, the compression of the fluid is performed by one or more moving pistons with reciprocating movement within a respective cylinder. The fluid to be compressed is suctioned into the cylinder by a suctioning pipe, while the compressed one is ejected from the cylinder towards a discharge pipe. Usually, the piston or pistons of a reciprocating compressor are operated by electric motors or by internal combustion engines through a crankshaft for transmitting drive and a traditional connecting rod/crank mechanism.

The industrial reciprocating compressors are usually provided with an external casing, referred to as frame, whose purpose is to accommodate the connecting rod/crank mechanism and bear the cylinder or cylinders, countering the reciprocating forces generated upon compression of the fluid.

As of date, the frames for reciprocating compressors, generally made by melting metal and/or machining by means of tool machines, are made up of a single body capable of resisting against the stresses generated during the compression cycle and subsequent to the rotational movement of the driving shaft for transmitting drive to the pistons. Thus each single compressor must be provided with a specific frame depending on the number of cylinders, usually arranged vertically and in a linear manner, with which it is provided. Consequently, it is necessary to design and manufacture each frame separately, substantially increasing both the costs and the production time.

Thus, the objective of the present invention is to provide a frame for fluid machines, in particular but not exclusively reciprocating compressors, capable of being used indistinctively both on single-cylinder machines and on two or multi-cylinder machines, without requiring different dies to obtain the specific frames depending on the number of cylinders of the machine.

Another objective of the invention is to provide a frame for fluid machines capable of facilitating and quickening the assembly of the machine with respect to known art.

Still, another objective of the invention is to provide a frame for a fluid machine capable of allowing reduction of costs and production time as well as storage in the warehouse.

These objectives according to the present invention are attained by manufacturing a frame for fluid machines, in particular but not exclusively reciprocating compressors, as described in claim 1.

Further characteristics of the invention are outlined by the subsequent claims.

Characteristics and advantages of a frame for fluid machines, in particular but not exclusively reciprocating compressors, according to the present invention shall be clearer from the following exemplifying and non-limiting description with reference to the schematic drawings attached wherein:

FIG. 1A is a top plan view of a frame for fluid machines according to the present invention, applied to a single-cylinder reciprocating compressor;

FIG. 1B is a sectional view obtained along line A-A of FIG. 1A;

FIG. 2A is a top plan view of a frame for fluid machines according to the present invention, applied to a two-cylinder reciprocating compressor;

FIG. 2B is a sectional view obtained along line A-A of FIG. 2A;

FIG. 3A is a top plan view of a frame for fluid machines according to the present invention, applied to a four-cylinder reciprocating compressor;

FIG. 3B is a sectional view obtained along line A-A of FIG. 3A;

FIG. 4 is a side elevation view of a frame for fluid machines according to the present invention; and

FIG. 5 is a side elevation view of a frame for fluid machines according to the present invention, on which one or more cylinders of fluid machines of a reciprocating type are vertically mounted.

Referring to the figures, schematically shown is a frame for fluid machines, indicated in its entirety with reference number 10 and applied as an example to a vertical reciprocating compressor for compressible fluids, which can be used in any gas compression station or system.

The frame 10 is provided to bear one or more cylinders 12, moving inside each of which, with a reciprocating movement, is a piston (not shown); operated by a crankshaft 14. The fluid to be compressed is introduced into each cylinder 12 through one of more suctioning pipes 18, while the compressed fluid is ejected from the cylinder 12 itself towards one or more discharge pipes 18′.

According to the invention, the frame 10 is made up of one or more modules 20 of the same shape and size, within each module 20 being provided a single chamber 16 adapted to accommodate the crank mechanisms of each single cylinder 12. In addition, each module 20 is provided with a pair of substantially flat opposite side walls 22 and 24 and with one or more fixing means 26 which allow rigid coupling to each other, adjacently arranging their respective side walls, of two or more identical modules 20 to provide a frame 10 for compressors provided with two or more cylinders 12, as shown for example in FIGS. 2A, 2B, 3A and 3B.

In the embodiments illustrated the fixing means 26, preferably made up of bolts of the known type, are inserted into suitable holes 26′ made on each side wall 22, 24 of each module 20, thus allowing to arrange the modules 20 themselves adjacent to each other in such a manner to provide frames 10 for reciprocating compressors provided with two cylinders (FIGS. 2A and 2B), three cylinders, four cylinders (FIGS. 3A and 3B) and more, without any restriction regarding the number of cylinders.

In such manner, it is possible to adapt the frame 10 according to the invention in a flexible manner to various types of reciprocating compressors, both with one or more cylinders, without requiring different frames depending of the number of cylinders of the machine.

Each of the identical modules 20 making up the frame 10 according to the invention can be made according to methods known to the industry, for example through melting metal (cast iron) or through machining by means of tool machines. In order to facilitate the coupling of the modules 20 in case of multi-cylinder compressors, made on one of the side walls 22 of each single module 20 can be at least one shaped portion 28 which is inserted in a shape-coupling manner into a respective shaped portion 30 provided on the other side wall 24 of the adjacent module 20. Due to the minimum clearance between the shaped portions 28 and 30 and the presence of one or more centering pins 32 fitted onto the side walls 22 and 24, as well as the presence of the fixing bolts 26 and the friction forces generated between the adjacent walls 22 and 24 of the adjacent modules 20, the modules 20 of the frame 10 are capable of efficiently resisting, when coupled to each other, against the forces generated during the operation cycle of the compressor just like the case single-block frames according to the known art.

Furthermore, each module 20 is provided, on each of its side walls 22 and 24, with a circular hole 34 which allows the passage of the crankshaft 14 and possibly one or more rotating countershafts, if present on the compressor. In order to prevent excessive flexure stress of the crankshaft 14 during the operation of the machine there can be provided one or more support plates 36 which can be inserted into the holes 34. The support plates 36 of the crankshaft 14 are fixed into the side walls 22 and 24 of each module 20 by means of a plurality of bolts 38. In addition, when the modules 20 are coupled to each other to provide a frame 10 adapted to support more cylinders 12 and, consequently, when the holes 34 of the modules 20 adjacent to each other are connected to each other to allow the passage of the crankshaft 14 (FIGS. 2B and 3B), support bearings 40, inserted into the holes 34, can be provided to support the crankshaft 14 itself.

It has thus been observed that the frame for fluid machines, in particular but not exclusively reciprocating compressors, according to the present invention attains the objectives outlined previously. In detail, the use of a single metal module made from a single die allows to provide, in an easy and quick manner, modular frames for machines with any number of cylinders. This occurs simply by assembling a number of modules corresponding to the number of cylinders of the machine to each other.

The frame for fluid machines, in particular but not exclusively reciprocating compressors, of the present invention thus conceived is in any case susceptible to various modifications and variants, all falling within the same invention concept; furthermore, all the details can be replaced by technically equivalent elements. In practice, the materials used, alongside their dimensions and shapes, may vary depending on the technical requirements.

Therefore, the scope of protection of the invention is defined by the attached claims. 

1. Reciprocating compressor for compressible fluids, comprising a frame (10) bearing one or more cylinders (12) moving inside each of which, with a reciprocating movement, is a piston operated by a crankshaft (14), the fluid to be compressed by said compressor being introduced into each cylinder (12) through one or more suctioning pipes (18), while the fluid compressed by said compressor being ejected from said cylinder (12) towards one or more discharge pipes (18′), characterised in that said frame (10) is made up of one or more modules (20) of the same size and shape, within each one of said modules (20) being provided a single chamber (16) adapted to accommodate the crank mechanisms of each of said cylinders (12), each of said modules (20) being further provided with a pair of opposite side walls (22, 24) and with one or more fixing means (26) which allow rigid coupling to each other, adjacently arranging their respective side walls (22, 24), of two or more of said identical modules (20) for providing a frame (10) for reciprocating compressors provided with two or more cylinders (12).
 2. Reciprocating compressor according to claim 1, characterised in that said fixing means (26) are inserted into suitable holes (26′) made on each of said opposite side walls (22, 24) of each of said modules (20).
 3. Reciprocating compressor according to claim 1, characterised in that made on one of said side walls (22) of each of said modules (20) is at least one shaped portion (28) which is inserted in a shape-coupling manner into a respective shaped portion (30) obtained on the other shaped portion of said side walls (26) of the adjacent module (20), in order to facilitate the coupling of said modules (20) when using fluid machines provided with two or more cylinders (12).
 4. Reciprocating compressor according to claim 3, characterised in that fitted on each of said opposite side walls (22, 24) are one or more centering pins (32).
 5. Reciprocating compressor according to claim 1, characterised in that each of said modules (20) is provided, on each of said opposite side walls (22, 24), with a circular hole (34) which allows the passage of said crankshaft (14).
 6. Reciprocating compressor according to claim 5, characterised in that inserted inside each of said circular holes (34) is a support plate (36) for said crankshaft (14) to prevent excessive flexure stress of said crankshaft (14) during the operation of said fluid machine.
 7. Reciprocating compressor according to claim 6, characterised in that said support plate (36) for said crankshaft (14) is fixed onto each of said opposite side walls (22, 24) by means of a plurality of bolts (38).
 8. Reciprocating compressor according to claim 5, characterised in that inserted inside each of said circular holes (34) are one or more support bearings (40) for said crankshaft (14) when said modules (20) are coupled to each other to provide a frame (10) for reciprocating compressors provided with two or more cylinders (12).
 9. Reciprocating compressor according to claim 1, characterised in that said frame (10) is made through melting metal.
 10. Reciprocating compressor according to claim 1, characterised in that said frame (10) is made through machining by means of tool machines. 